Spire
are an interesting cooler company because they produce such a wide variety of heatsinks. For
example, some past models have been pretty poorly finished and capable
of only moderate performance at best. Recent models have made significant
improvements on quality control standards, and better designs
have improved thermal performance greatly.

Take for example the SB420B8 below; this is an
interlocking copper fin heatsink with an aluminum shroud (don't be fooled by that
copper-coloured anodizing). The fins come off the assembly line interlocked with
one anther via small tabs and the entire fin assembly is soldered to the copper
base plate.

Sitting on top of it all is a 25mm thick 70mm fan
that hums away rather quietly.

As we
mentioned just a second ago, the method used to attach the thin copper fins to this
3mm thick copper base relies upon the fins interlocking with one another. We first
saw this method displayed by a company at Comdex 2000, and since then it
has become very popular, no doubt because it involves stamped fins made from inexpensive sheet
copper.

To keep
costs (and weight) down the copper-fin and base assembly is protected with an anodized
aluminum fan shroud. The aluminum fan shroud it attached with a few
screws to the base and provides the necessary stand off above the fin
tips for proper air flow as well.